Charles Ellicott Commentary Luke 22:32

"but I made supplication for thee, that thy faith fail not; and do thou, when once thou hast turned again, establish thy brethren." — Luke 22:32 (ASV)

I have prayed for thee.—The individualising pronoun is significant as indicating to the Apostle, who was most confident, it may be, of his claim to greatness, that he, of the whole company of the Twelve, was in the greatest danger. In the Greek, the other pronoun is also emphatic: “It was I who prayed for thee.” The prayer was answered, and the words that follow assume the answer as certain.

In one sense, “faith” did “fail” when the disciple denied his Lord; but repentance came after it, and a new power was gained through that weakness to make others strong. The word for “strengthen” is not found in the other Gospels but is used frequently by St. Paul (Romans 1:11; 1 Thessalonians 3:2, and elsewhere), and twice by St. Peter himself (1 Peter 5:10; 2 Peter 1:12).